HERPETOLOGICAL JOURNAL, Vol. 16, pp. 183-189 (2006) A NEW SPECIES OF ARBOREAL LEPTOPELIS (ANURA: ARTHROLEPTIDAE) FROM THE FORESTS OF WESTERN KENYA JÖRN KÖHLER1,2, BERYL A. BWONG3, SUSANNE SCHICK4, MICHAEL VEITH4 AND STEFAN LÖTTERS4 1Department of Zoology, Hessisches Landesmuseum Darmstadt, Darmstadt, Germany 2Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany 3Department of Herpetology, National Museums of Kenya, Nairobi, Kenya 4Zoological Institute, Department of Ecology, Mainz University, Mainz, Germany A new species of arboreal Leptopelis is described from Kakamega Forest, western Kenya. It is a small, brown forest species formerly referred to L. modestus, but distinguished by differences in advertisement call and the sequence of the mitochondrial 16S rRNA gene. The specific allocation of certain related populations of Leptopelis in East and West Africa is briefly discussed. Key words: Amphibia, bioacoustics, DNA, systematics, taxonomy INTRODUCTION The confusing systematic status of East African The Kakamega Forest in western Kenya is an iso- Leptopelis modestus-like frogs led us to reinvestigate lated forest remnant of the Guineo-Congolean the status of the Kakamega Forest population. We con- rainforest belt. Its herpetofauna exhibits strong relation- cluded that it represents an unnamed species, which we ships with Central Africa (Köhler et al., 2003). describe here. Currently, 27 anuran species are known from the MATERIALS AND METHODS Kakamega Forest and its vicinity (unpubl. data). Among them are two species of the genus Leptopelis Specimens examined are deposited at the National Günther. Schiøtz (1975) tentatively referred the Museums of Kenya, Nairobi (NMK), the Zoologisches populations from Kakamega Forest to the terrestrial Forschungsmuseum Alexander Koenig, Bonn (ZFMK) Leptopelis bocagii (Günther, 1864) and the arboreal L. and the Zoologisches Museum Berlin (ZMB). modestus (Werner, 1898). The author noted morpho- Field work was carried out in May and July 2004 at logical differences in the Kakamega Forest population Buyangu Hill, northern Kakamega Forest (00°21'20'' of L. bocagii, which exhibits green instead of the brown N, 34°52'40'' E, ca. 1650 m above sea level). Adult dorsal coloration present in other areas. Schiøtz (1975) specimens collected by us were preserved in 70% noted that the sample of L. modestus from Kakamega is methanol; the single tadpole collected was stored in very similar to L. modestus specimens collected by him 4% formalin. A toe of one adult and the tail tip of the in Obuda, Nigeria, as well as to specimens from the tadpole were clipped and stored in 98% ethanol for ge- eastern Democratic Republic of Congo, which were al- netic analysis. located to L. modestus by Laurent (1973). Later, The terminology and description scheme follow Schiøtz (1999) stated that the Nigerian populations are those of Lötters et al. (2005). The webbing formula is not conspecific with L. modestus and argued that East according to Glaw & Vences (1994). Measurements African populations may also be distinct, mainly be- are in millimetres and were taken as described by cause such an apparently discontinuous distribution Lötters et al. (in press) with dial callipers to the nearest pattern seems unlikely. 0.1 mm. The snout-vent length is abbreviated SVL. Leptopelis modestus was originally described from Larval staging follows Gosner (1960). Tadpole body Cameroon by Werner (1898). The type locality was measurements were taken under a stereoscope. later restricted to “Buea, Cameroon” by lectotype des- Preserved tissue was used to sequence a 515 bp ignation (Perret, 1962). Perret (1962, 1966) considered fragment of mitochondrial DNA, using the 16S rRNA L. modestus a forest species endemic to the southern gene; the allocation of the tadpole to the new species Cameroon highlands. This view was adopted by Schiøtz was confirmed by comparison of the respective DNA (1999), who argued that the name L. modestus may re- sequences. For methods and primers used see Lötters fer to more than one species. However, at the same time, et al. (2004). Schiøtz (1999) continued to use the name L. modestus In July 2004, we recorded advertisement calls in the for the populations from Nigeria and Kakamega Forest, field from a chorus of males (recorded male not col- Kenya. lected) using a digital Sharp MD-SR70 recorder and a Sennheiser Me-66 directional microphone. Air tem- Correspondence: J. Köhler, Department of Zoology, perature at approximately 1.0 m above ground was Hessisches Landesmuseum Darmstadt, Friedensplatz 1, measured with a Greisinger GFTH 95 immediately af- 64283 Darmstadt, Germany. E-mail: [email protected] ter recording. Recordings were sampled at a rate of 184 J. KÖHLER ET AL. function with 256 bands resolution. Terminology in call descriptions follows Heyer et al. (1990) as extended by Köhler (2000). SYSTEMATICS LEPTOPELIS MACKAYI SP. N. (FIG. 1). Leptopelis modestus (non Werner): Schiøtz, 1975:27 (partim); 1999:269 (partim). Holotype. NMK A/3057/1, adult male, from Rondo Retreat Centre, Isecheno, 00°12'39'' N, 34°46'36'' E, 1550 m a.s.l., southern Kakamega Forest, Kakamega District, Western Province, Kenya; collected on 7 No- vember 1994 by K. Howell. Paratypes. NMK A/1407/1-2, adult and subadult males, NMK A/1407/3, adult female, from Bukura, Kakamega District, Western Province, Kenya, col- lected on 18 March 1983 by T. Madsen; ZFMK 83304-305, two adult males, from the northern slope of Buyangu Hill, northern Kakamega Forest, Kakamega District, Western Province, Kenya, collected on 18 and 30 May 2004 by B. A. Bwong. Referred specimens. NMK A/3072/1, male (desic- cated), from the Kakamega Forest (no precise locality data), Kakamega District, Western Province, Kenya, collected 1971 by A. Schiøtz; ZFMK 83306, tadpole in Stage 27, from the northern slope of Buyangu Hill, northern Kakamega Forest, Kakamega District, West- ern Province, Kenya, collected on 3 July 2004 by S. Schick and S. Lötters. Diagnosis. A small arboreal Leptopelis with (1) adult males SVL 29–36 mm; adult female SVL about 40 mm; (2) head wider than long; (3) eye relatively large with horizontal eye diameter almost twice the distance from nostril to anterior corner of eye; (4) dorsal snout shape rounded; (5) tympanum distinct, its horizontal di- ameter slightly less than half the eye diameter; (6) dorsal skin finely granular, with small scattered tuber- cles; (7) feet one half webbed, hands one fourth webbed; (8) well-developed subarticular tubercles and terminal discs present on all toes and fingers; (9) pecto- ral glands present in males; (10) colour in life dorsally tan with brown markings; white fleck present below eye; laterally cream with small brown and whitish fleck- ing; ventrally creamy white with few scattered brown flecks; iris bronze with fine black reticulation, eye pe- riphery black; (11) vomerine odontophores distinct, forming two separate short rows, median between choa- nae; (12) sequence of a 515 bp fragment of the FIG. 1. Dorsal (A) and ventral views (B), as well as lateral mitochondrial 16S rRNA gene as stored at GenBank view of head (C) of the preserved male holotype of Leptopelis (accession number AY940089). mackayi sp. n. (NMK A/3057/1; SVL 34.0 mm). See Schiøtz Leptopelis mackayi is most similar to L. modestus (1999:271) for colour illustration of a live specimen of L. from Cameroon to which it was formerly referred; the mackayi (as L. modestus). two differ in advertisement call characters and the se- 22.05 kHz and 16-bit resolution and analysed with the quence of the mitochondrial 16S rRNA gene (see sound analysis software Cool Edit 96 (Syntrillium Soft- below). Furthermore, L. modestus usually has lighter ware Corp.). Frequency information was obtained dorsal coloration and less tubercular dorsal skin com- through Fast Fourier Transformation (FFT, width 1024 pared to the new species. Leptopelis fiziensis Laurent, points). Spectral settings in figures are Hanning window 1973, a taxon originally described as a subspecies of L. NEW LEPTOPELIS FROM KENYA 185 modestus, differs from the new species in its slightly trils directed laterally, visible from dorsal view; canthus larger size, a somewhat more robust body and a grey rostralis slightly curved; loreal region concave; eye vocal sac in life. Leptopelis christyi (Boulenger, 1912) relatively large with horizontal eye diameter almost from Uganda and the eastern Democratic Republic of twice the distance from nostril to anterior corner of eye; Congo differs from the species described herein in its pupil vertical; tympanum distinct, round, its diameter larger size, different dorsal colour pattern, white or yel- less than half of eye diameter, tympanic annulus low finger and toe discs in life and in advertisement call present; skin of all dorsal surfaces finely granular, with characters (Schiøtz, 1975, 1999; Köhler et al., 2005). scattered small tubercles on dorsum; skin on ventral sur- Other similar East African Leptopelis include L. faces granular; pectoral glands present; hind limbs kivuensis Ahl, 1929, and L. karissimbensis Ahl, 1929. relatively long with tibia length reaching almost half The latter species inhabits montane grasslands and dif- SVL, tibiotarsal articulation reaching posterior corner fers from L. mackayi in advertisement call of eye when hind limb adpressed; foot webbing formula characteristics (Schiøtz, 1975), a smaller tympanum 1(0), 2i(1) 2e(0), 3i(2) 3e(½), 4i(2) 4e(2), 5(½), all toes and a more tuberculate dorsum. Like L. mackayi, L. with lateral fringes;